This invention relates generally to the field of telephony, and more particularly to an improved self-contained circuit element adapted to be used in conjunction with a telephone network interface device of a type normally installed at the premises of a subscriber. Circuit elements of this type are used, for example, to open the subscriber line at the subscriber premises for purposes of testing the telephone company portion of the line for the existence of faults independently of testing subscriber owned equipment.
In many of such interface devices, the interface housing is provided with an inner wall, one surface of which includes a pair of opposed slot-forming members which support the circuit element against the inner wall in such manner that projecting leads of the circuit board may be readily interconnected to adjacent screw terminals. While the slot forming means in interface housings of any given manufacturer are normally within close commercial tolerances, where the circuit board housing is to be installed in interface housing of different manufacture, the range of clearance which must be accommodated is excessive, in some cases to a degree that precludes engagement of the circuit board housing without damage.